The present disclosure relates to a power supply system and an image forming apparatus having the power supply system, and more particularly, to a technology of detecting a zero cross point of an alternating current voltage.
For example, JP-A-2010-239774 discloses a technology of detecting a zero cross point (zero cross timing) of an alternating current voltage. In the technical document, the zero cross point of the alternating current voltage is detected using a photo coupler.